Oxy-fuel combustion with integrated pollution control

ABSTRACT

An oxygen fueled integrated pollutant removal and combustion system includes a combustion system and an integrated pollutant removal system. The combustion system includes a furnace having at least one burner that is configured to substantially prevent the introduction of air. An oxygen supply supplies oxygen at a predetermine purity greater than 21 percent and a carbon based fuel supply supplies a carbon based fuel. Oxygen and fuel are fed into the furnace in controlled proportion to each other and combustion is controlled to produce a flame temperature in excess The integrated. pollutant removal system includes at least one direct contact heat exchanger for bringing the flue gas into intimated contact with a cooling liquid to produce a pollutant-laden liquid stream and a stripped flue gas stream and at least one compressor for receiving and compressing the stripped flue gas stream.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/306,437, filed on Dec. 28, 2005, now U.S. Pat. No. 8,087,926, herebyincorporated by reference.

BACKGROUND OF THE INVENTION

The present invention pertains to an integrated oxygen fueled combustionand pollution control system. More particularly, the present inventionpertains to an oxy-fueled combustion system having integrated pollutioncontrol to effectively reduce, to near zero, emissions from combustionsources.

Oxy-fueled combustion systems are known in the art. Such systems useessentially pure oxygen for combustion with fuel in near stoichiometricproportions and at high flame temperatures for high efficiency energyproduction. Oxy-fuel systems are used in boilers to produce steam forelectrical generation and in industrial settings, such as in aluminumrecycling to melt aluminum for recasting. It is also contemplated thatoxy-fueled combustion can be used for waste incineration as well asother industrial and environmental applications. Oxy-fuel technology anduses for this technology are disclosed in Gross, U.S. Pat. Nos.6,436,337, 6,596,220, 6,797,228 and 6,818,176, all of which are commonlyowned with the present application and are incorporated herein byreference.

Advantageously, because oxy-fuel combustion uses oxygen rather than airas an oxygen source, there is concomitant reduction in flue gasproduced. In addition, combustion is carried out so that the NOxcombustion products are near zero and are due almost exclusively tofuel-borne nitrogen. That is, because oxygen rather than air is used asan oxygen source, there is less mass flow and no nitrogen to contributeto the formation of NOx.

Although oxy-fuel combustion provides fuel efficient and reducedemission energy generation, there is still a fairly substantial amountof emissions that are produced during the combustion process. Inaddition, because the volume of gas is less, due to the use of oxygeninstead of air, the concentration of other pollutants is higher. Forexample, the mass of SOx and particulate matter will not change,however, the concentration will increase because of the reduced overallvolume.

Pollution control or removal systems are known in the art. These systemscan, for example, use intimate contact between the flue gases anddownstream process equipment such as precipitators and scrubbers toremove particulate matter, sulfur containing compounds and mercurycontaining compounds. Other systems use serial compression stripping ofpollutants to remove pollutants and recover energy from the flue gasstream. Such a system is disclosed in Ochs, U.S. Pat. No. 6,898,936,incorporated herein by reference.

Accordingly, there is a need for a combustion system that produces lowflue gas volume with integrated pollution removal. Desirably, such asystem takes advantage of known combustion and pollution control systemsto provide fuel efficient energy production in conjunction with reducedpollutant production and capture of the remaining pollutants that areproduced.

BRIEF SUMMARY OF THE INVENTION

An integrated oxygen fueled combustion system and pollutant removalsystem, reduces flue gas volumes, eliminates NOx and capture condensablegases. The system includes a combustion system having a furnace with atleast one burner that is configured to substantially prevent theintroduction of air. An oxygen supply supplies oxygen at a predeterminepurity greater than 21 percent and a carbon basea fuel supply supplies acarbon based fuel. Oxygen and fuel are fed into the furnace incontrolled proportion to each other. Combustion is controlled to producea flame temperature in excess of 3000 degrees F. and a flue gas streamcontaining CO2 and other gases and is substantially void of non-fuelborne nitrogen containing combustion produced gaseous compounds.

The pollutant removal system includes at least one direct contact heatexchanger for bringing the flue gas into intimated contact with acooling liquid, preferably water, to produce a pollutant-laden liquidstream and a stripped flue gas stream. The system includes at least onecompressor for receiving and compressing the stripped flue gas stream.

Preferably, the system includes a series of heat exchangers andcompressors to cool and compress the flue gas. The flue gas can becooled and compressed to and the stripped flue gas stream can separatedinto non-condensable gases and condensable gases. The condensable gases,in large part CO2, are condensed into a substantially liquid state andcan be sequestered. The CO2 can be recirculated, in part, to carry asolid fuel such as coal into the furnace.

A method oxy-fuel combustion integrated with pollutant removal includesproviding a furnace having at least one burner, and configured tosubstantially prevent the introduction of air, providing an oxygensupply for supplying oxygen at a predetermine purity greater than 21percent and providing a carbon based fuel supply for supplying a carbonbased fuel.

Either or both of the oxygen and carbon based fuel are limited to lessthan 5 percent over the stoichiometric proportion and combustion iscontrolled to produce a flame temperature in excess of 3000 degrees F.and a flue gas stream containing CO2 and other gases and substantiallyvoid of non-fuel borne nitrogen containing combustion produced gaseouscompounds.

The pollutant removal system is provided which includes a direct contactheat exchanger in serial arrangement with a compressor. The flue gas isbrought into intimated contact with a cooling liquid, preferably water,in the heat exchanger to produce a pollutant-laden liquid stream and astripped flue gas stream. The stripped flue gas stream is fed into thecompressor to compress the stripped flue gas stream.

In a preferred method, the steps of cooling the stripped flue gas streamand compressing the cooled stripped flue gas stream are carried out aswell as sequestering the compressed cooled stripped flue gas stream.

These and other features and advantages of the present invention will beapparent from the following detailed description, in conjunction withthe appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The benefits and advantages of the present invention will become morereadily apparent to those of ordinary skill in the relevant art afterreviewing the following detailed description and accompanying drawings,wherein:

FIG. 1 is flow diagram of an integrated oxy-fuel combustion andpollutant removal system that was assembled for testing the principlesof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention is susceptible of embodiment in variousforms, there is shown in the drawings and will hereinafter be describeda presently preferred embodiment with the understanding that the presentdisclosure is to be considered an exemplification of the invention andis not intended to limit the invention to the specific embodimentillustrated. It should be further understood that the title of thissection of this specification, namely, “Detailed Description Of TheInvention”, relates to a requirement of the United States Patent Office,and does not imply, nor should be inferred to limit the subject matterdisclosed herein.

As discussed in the aforementioned patents to Gross, an oxy-fuelcombustion system uses essentially pure oxygen, in combination with afuel source to produce heat, by flame production (i.e., combustion), inan efficient, environmentally non-adverse manner. Oxygen, which issupplied by an oxidizing agent, in concentrations of about 85 percent toabout 99+ percent can be used, however, it is preferable to have oxygenconcentration (i.e., oxygen supply purity) as high as possible.

In such a system, high-purity oxygen is fed, along with the fuel sourcein stoichiometric proportions, into a burner in a furnace. The oxygenand fuel is ignited to release the energy stored in the fuel. Forpurposes of the present disclosure, reference to furnace is to bebroadly interpreted to include any industrial or commercial heatgenerator that combusts fossil (carbon-based) fuel. For example,water-tube-walled boilers for electrical power generation, as well asdirect fired furnaces for industrial applications are contemplated touse the oxy-fueled combustion system. In a preferred system, oxygenconcentration or purity is as high as practicable to reduce green-housegas production.

It is contemplated that essentially any fuel source can be used. Forexample, oxygen can be fed along with natural gas, for combustion in afurnace. Other fuel sources contemplated include oils including refinedas well as waste oils, wood, coal, coal dust, refuse (garbage waste),animal wastes and products and the like. Those skilled in the art willrecognize the myriad fuel sources that can be used with the presentoxy-fuel system.

Compared to conventional combustion processes which use air as anoxidizing agent to supply oxygen, rather than essentially pure oxygen,for combustion, the oxy-fuel system has an overall flow throughput thatis greatly reduced. The oxygen component of air (about 21 percent) isused in combustion, while the remaining components (essentiallynitrogen) are heated in and exhausted from the furnace. Moreover, thepresent process uses oxygen in a stoichiometric proportion to the fuel.That is, only enough oxygen is fed in proportion to the fuel to assurecomplete combustion of the fuel. Thus, no “excess” oxygen is fed intothe combustion system.

Many advantages and benefits are achieved using the oxy-fuel combustionsystem. Aside from increased efficiency (or conversely reduced fuelconsumption to produce an equivalent amount of power), because of thereduced input of gas, there is a dramatic decrease in the volume of fluegas. Based on the difference between using air which is 21 percentoxygen and pure oxygen, the volumetric flow rate is about one-fifth (⅕)using an oxy-fuel combustion system, compared to a conventional air-fedcombustion system. In addition, because there is no energy absorbed bynon-combustion related materials (e.g., excess oxygen or nitrogen), moreenergy is available for the underlying process.

Advantageously, the reduced gas volume (and thus flue gas volume) alsoincreases the residence time of the gases in the furnace or boiler toprovide additional opportunity for heat transfer.

In that the overall flue gas volume is so greatly reduced, highlyefficient downstream processing that would otherwise not be available orwould be impractical can now be used in large scale industrial and powergeneration settings.

Accordingly, the present invention uses oxy-fuel combustion inconjunction with the removal of multiple pollutants through theintegrated condensation of H2O and CO2 with entrainment of particulatesand dissolution and condensation of other pollutants including SO2. Sucha pollutant removal system and method is disclosed in the aforementionedpatent to Ochs et al.

Consolidating the removal of pollutants into one process has thepotential to reduce costs and reduce power requirements for operation ofsuch a system. Non-condensable combustion products including oxygen andargon may be present in combustion products. Although the oxy-fuelcombustion system is operated at or very near stoichiometry (preferablywithin 5 percent of stoichiometry), oxygen may be present in the fluegas. Argon can come from the air separation process (remaining in theproduced oxygen). Some relatively small amounts of nitrogen may also bepresent as fuel-borne or as air in-leakage into the underlying processequipment.

Condensable vapors such as H2O, CO2, SOx, and although minimal, NOx, areproduced in the combustion process and are the targets for condensation.When referring to combustion products in this invention it is assumedthat these condensable vapors and non-condensable gases are present aswell as particulates and other pollutants.

The pollutant control portion of the system can also accomplishremediation and recovery of energy from combustion products from afossil fuel power plant having a fossil fuel combustion chamber (e.g., aboiler, furnace, combustion turbine or the like), a compressor, aturbine, a heat exchanger, and a source of oxygen (which could be an airseparation unit). Those skilled in the art will understand andappreciate that reference to, for example, a compressor, includes morethan one compressor.

The fossil fuel power plant combustion products can includenon-condensable gases such as oxygen and argon; condensable vapors suchas water vapor and acid gases such as SOX and (again, although minimal,NOX); and CO2 and pollutants such as particulates and mercury. Theprocess of pollutant removal and sequestration, includes changing thetemperature and/or pressure of the combustion products by cooling and/orcompressing the combustion products to a temperature/pressurecombination below the dew point of some or all of the condensablevapors.

This process is carried out to condense liquid having some acid gasesdissolved and/or entrained therein and/or directly condensing the acidgases (such as CO2 and SO2) from the combustion products. It is carriedout further to dissolve some of the pollutants thus recovering thecombustion products. Dissolve in the context of this disclosure means toentrain and/or dissolve.

This process is repeated through one or more of cooling and/orcompressing steps with condensation and separation of condensable vaporsand acid gases. The recovery of heat in the form of either latent and/orsensible heat cab also be accomplished. The condensation reduces theenergy required for continued compression by reducing mass andtemperature, until the partially remediated flue gas is CO2, SO2, andH2O poor. Thereafter the remaining flue gases are sent to an exhaust.

The fossil fuel can be any of those discussed above. In certaininstances, the pollutants will include fine particulate matter and/orheavy metals such as mercury other metals such as vanadium.

The present invention also relates to a method of applying energy savingtechniques, during flue gas recirculation and pollutant removal, suchthat power generation systems can improve substantially in efficiency.For example, in the case of a subcritical pulverized coal (PC) systemwithout energy recovery, the performance can drop from 38.3% thermalefficiency (for a modern system without CO2 removal) to as low as 20.0%(for the system with CO2 removal and no energy recovery). A systemaccording to one embodiment of the present invention can perform at29.6% (with CO2 removal) when energy recovery is included in the modeldesign. it is anticipated that better efficiencies will be achieved. Thepresent oxy-fuel combustion with integrated pollution control isapplicable to new construction, repowering, and retrofits.

In an exemplary system using the present oxy-fuel and IPR process, fluegases as described in the table below are predicted. The flue gases willexit from the combustion region or furnace area, where they would passthrough a cyclone/bag house or electrostatic precipitator for grossparticulate removal. The combustion gas then passes through a directcontact heat exchanger (DCHX). In this unit the flue gases come intocontact with a cooler liquid. This cooling step allows the vapors tocondense. The step also allows for dissolving the entrained solublepollutants and fine particles.

The gases exiting the first column are now cleaner and substantiallypollutant free. These gases are compressed and can proceed into asuccessive DCHX and compression step. A final compression and heatexchange step is used to separate the oxygen, argon, and nitrogen(minimal) from the CO2. Also a mercury trap is used to remove gaseousmercury before release to atmosphere.

The table below shows the expected results as a comparison of thepresent oxy-fuel combustion and IPR system to a conventional air fueledcombustion process. As the results show, the volume of flue gas at theoutset, is less in the oxy-fuel combustion system by virtue of theelimination of nitrogen from the input stream. In the present system,the IPR serves to further reduce the volume and gas flow throughsuccessive compression and cooling stages. As the flue gases progressthrough the combined processes the final product is captured CO2 forsequestration.

TABLE 1 A COMPARISON OF THE PROPERTIES AND COMPOSITIONS OF IPR-TREATEDOXY- FUEL COMBUSTION PRODUCTS WITH THOSE FROM A CONVENTIONAL COAL FIREDBOILER Conventional after After 1^(st) After 2^(nd) After 3^(rd)economizer Oxyfuel exhaust compression compression compression Gas Flow(kg/hr) 1,716,395 686,985 364,367 354,854 353,630 Vol flow (m³/hr)1,932,442 826,995 72,623 15,944 661 Inlet Pressure 14.62 15.51 62 2641,500 (psia) Inlet Temp. (° F.) 270 800 342 323 88.2 Density (kg/m³)0.8882 0.8307 5.02 22.26 534.61 H₂O (fraction) 0.0832 0.33222 0.06950.00994 0.0004 Ar (fraction) 0.0088 0.01152 0.0163 0.01730 0.0175 CO₂(fraction) 0.1368 0.61309 0.8662 0.92161 0.9305 N₂ (fraction) 0.73420.00904 0.0128 0.01359 0.0137 O₂ (fraction) 0.0350 0.02499 0.03530.03755 0.0379 SO₂ (fraction) 0.0020 0.00913 0.0000 0.00000 0.0000

As can be seen from the data of Table 1, the volume of the combustionproducts has dropped significantly as a result of the successivecompressing and cooling stages. The result is a capture of CO2 andsubsequent sequestration, which is the ultimate goal. The CO2 thusresulting can be stored or used in, for example, a commercial orindustrial application.

A test system 10 was constructed to determine the actual resultsvis-à-vis oxy-fuel combustion in conjunction with CO2 sequestration andpollutant removal. A schematic of the test system is illustrated inFIG. 1. The system 10 includes an oxy-fueled combustor 12 having a coalfeed 14 (with CO2 as the carrier gas 16), and an oxygen feed 18. Coalwas fed at a rate of 27 lbs per hour (pph), carried by CO2 at a rate of40 pph, and oxygen at a rate of 52 pph. In that the system 10 was a testsystem rather than a commercial or industrial system (for example, acommercial boiler for electrical generation), the combustor 12 wascooled with cooling water to serve as an energy/heat sink.

The combustor exhaust 20 flowed to a cyclone/bag house 22 at which ash(as at 24) was removed at a rate of about 1 pph. Following ash removal24, about 118 pph of combustion gases remained in the flue gas stream 26at an exit temperature that was less than about 300° F.

The remaining flue gases 26 were then fed to a direct contact heatexchanger 28 (the first heat exchanger). Water (indicated at 30) wassprayed directly into the hot flue gas stream 26. The cooling watercondensed some of the hot water vapor and further removed the solublepollutants and entrained particulate matter (see discharge at 32). About13 pph of water vapor was condensed in the first heat exchanger 28—theflue gases that remained 34 were present at a rate of about 105 pph.

Following exit from the first heat exchanger 28, the remaining gases 34were fed into a first, a low pressure compressor 36, (at an inletpressure of about atmospheric) and exited the compressor 36 at apressure of about 175 lbs per square inch gauge (psig). As a result ofthe compression stage, the temperature of the gases 38 increased. Theremaining flue gases were then fed into a second direct contact heatexchanger 40 where they were brought into intimate contact with acooling water stream as at 42. The exiting stream 44 released about anadditional 4 pph of water and thus had an exiting exhaust/flue gas 44flow rate of about 101 pph.

Following the second heat exchanger 40, the gases 44 were furthercompressed to about 250 psig at a second compressor 46. Although thesecond compression stage resulted in a temperature increase, it wasdetermined during testing that a third heat exchange step was notnecessary. It will be appreciated that in larger scale operation,however, such additional heat exchange/cooling stages may be necessary.

A third compression stage, at a third compressor 48 was then carried outon the remaining flue gases 50 to increase the pressure of the exitinggas stream 52 to about 680 psig. Again, it was determined that althoughthe temperature of the gases increased, active or direct cooling was notnecessary in that losses to ambient through the piping system carryingthe gases were sufficient to reduce the temperature of the gases.

A final compression, at a final compressor 52, of the gases was carriedout to increase the pressure of the gases to about 2000 psig. Followingthe final compression stage, the remaining gases 56 were fed into a heatexchanger 58, the final heat exchanger, in which the temperature of thestream 56 was reduced to below the dew point of the of the gases and asa result, condensation of the gases commenced. The condensate (as at60), which was principally liquefied CO2 (at a rate of 80 pph), wasextracted and sequestered. In the present case, the CO2 was bottled, andretained.

The non-condensable gases (as at 62), which included a small amount ofCO2, were passed through a mercury filter 64 and subsequently bled intoan accumulator 66. The accumulator 66 provided flexibility in control ofthe system flow rate. The exhaust 68 from the accumulator 66 wasdischarged to the atmosphere. The flow rate from the accumulator 66,normalized to steady state from the overall system, was about 21 pph.

It will be appreciated by those skilled in the art that theabove-presented exemplary system 10 was for testing and verificationpurposes and that the number and position of the compression and coolingstages can and likely will be changed to accommodate a particulardesired design and/or result. In addition, various chemical injectionpoints 70, filters 72, bypasses 74 and the like may also be incorporatedinto the system 10 and, accordingly, all such changes are within thescope and spirit of the present invention.

The projected fuel savings and other increased efficiencies of thepresent oxy-fuel combustion system with IPR are such that the cost ofthis combined process is anticipated to be competitive with currentcombustion technologies. Additionally, the prospect of new regulatoryrequirements are causing power plant designers to revisit theconventional approaches used to remove pollutants which would only serveto improve the economics behind this approach.

It will be appreciated that the use of oxy-fueled combustion systemswith IPR in many industrial and power generating applications canprovide reduced fuel consumption with equivalent power output or heatgeneration. Reduced fuel consumption, along with efficient use of thefuel (i.e., efficient combustion) and integrated IPR providessignificant reductions in overall operating costs, and reduced andsequestered emissions of other exhaust/flue gases.

Due to the variety of industrial fuels that can be used, such as coal,natural gas, various oils (heating and waste oil), wood and otherrecycled wastes, along with the various methods, current and proposed,to generate oxygen, those skilled in the art will recognize the enormouspotential, vis-à-vis commercial and industrial applicability, of thepresent combustion system. Fuel selection can be made based uponavailability, economic factors and environmental concerns. Thus, no onefuel is specified; rather a myriad, and in fact, all carbon based fuelsare compatible with the present system. Accordingly, the particulateremoval stages of the integrated IPR system may vary.

As to the supply of oxygen for the oxy-fueled burners (combustionsystem), there are many acceptable technologies for producing oxygen athigh purity levels, such as cryogenics, membrane systems, absorptionunits, hydrolysis and the like. All such fuel uses and oxygen suppliesare within the scope of the present invention.

In general, the use of oxygen fuel fired combustion over current ortraditional air fuel systems offers significant advantages in manyareas. First is the ability to run at precise stoichiometric levelswithout the hindrance of nitrogen in the combustion envelope. Thisallows for greater efficiency of the fuel usage, while greatly reducingthe NOx levels in the burn application. Significantly, less fuel isrequired to achieve the same levels of energy output, which in turn,reduces the overall operating costs. In using less fuel to render thesame power output, a natural reduction in emissions results. Fuelsavings and less emissions are but only two of the benefits provided bythe present system. In conjunction with the integrated pollutant removal(IPR) system, the present oxy-fuel IPR system provides far greaterlevels of efficiency and pollution control than known systems.

It is anticipated that combustors (e.g., boilers) will be designedaround oxygen fueled combustion systems with integrated IPR to take fulladvantage of the benefits of these systems. It is also anticipated thatretrofits or modifications to existing equipment will also provide manyof these benefits both to the operator (e.g., utility) and to theenvironment.

In the present disclosure, the words “a” or “an” are to be taken toinclude both the singular and the plural. Conversely, any reference toplural items shall, where appropriate, include the singular.

From the foregoing it will be observed that numerous modifications andvariations can be effectuated without departing from the true spirit andscope of the novel concepts of the present invention. It is to beunderstood that no limitation with respect to the specific embodimentsillustrated is intended or should be inferred. The disclosure isintended to cover by the appended claims all such modifications as fallwithin the scope of the claims.

What is claimed is:
 1. An oxygen fueled integrated pollutant removal andcombustion system comprising: a combustion system having at least oneburner, and configured to substantially prevent the introduction of air,an oxygen supply for supplying oxygen at a predetermine purity greaterthan 21 percent, a carbon based fuel supply for supplying a carbon basedfuel, a control system for feeding the oxygen and the carbon based fuelinto the at least one burner in controlled proportion to each other andcontrolling the combustion of the carbon based fuel to produce a flametemperature in excess of 3000 degrees F. and a flue gas streamcontaining CO₂ and other gases and substantially void of non-fuel bornenitrogen containing combustion produced gaseous compounds; and apollutant removal system for processing and separating condensable andnon-condensable vapors, said pollutant control system including at leastone direct contact heat exchanger for bringing the flue gas intointimated contact with a cooling liquid to produce a pollutant-ladenliquid stream and a stripped flue gas stream containing condensable andnon-condensable gases, said pollution removal system including adischarge for discharging said pollutant-laden liquid stream at leastone heat exchanger and compressor for receiving the stripped flue gasstream and separating said condensable and non-condensable vapors sothat said condensable vapors can be stored, said pollutant removalsystem also including and a trap for filtering and accumulatingnon-condensable vapors before said flue gas is exhausted to theatmosphere.
 2. The integrated combustion system in accordance with claim1 wherein the cooling liquid is water.
 3. The integrated combustionsystem in accordance with claim 1 including at least two compressors. 4.The integrated combustion system in accordance with claim 1 wherein thestripped flue gas stream is separated into non-condensable gases andcondensable gases.
 5. The integrated combustion system in accordancewith claim 4 wherein the condensable gases are condensed into asubstantially liquid state.
 6. The integrated combustion system inaccordance with claim 5 wherein the gases condensed into thesubstantially liquid state are sequestered.
 7. The integrated combustionsystem in accordance with claim 6 wherein the gases condensed into thesubstantially liquid state are, in large part, CO₂.
 8. The integratedcombustion system in accordance with claim 1 wherein the carbon basedfeel is a solid fuel and wherein the stripped flue gas stream isrecirculated, in part, to carry the carbon based fuel into thecombustion system.
 9. The integrated combustion system in accordancewith claim 8 wherein the stripped flue gas stream is substantially CO₂.10. The integrated combustion system in accordance with claim 1including a plurality of heat exchangers and compressors, wherein atleast two of the heat exchangers are direct contact heat exchangers forintimately contacting cooling water with the flue gas stream and whereinat least one compressor is disposed between the heat exchangers forcompressing the stripped flue gas stream between the heat exchangers.11. An oxygen fueled combustion system comprising: a combustion systemhaving a controlled environment with substantially no in-leakage from anexternal environment, and configured to substantially prevent theintroduction of air, an oxidizing agent supply for supplying oxygenhaving a predetermined purity and a carbon based fuel supply forsupplying a carbon based fuel and including a control system for feedingthe oxygen and the carbon based fuel into the furnace in astoichiometric proportion to one another limited to an excess of eitherthe oxygen or the carbon based fuel to less than 5 percent over thestoichiometric proportion, said combustion system configured so that theflue gas stream has substantially zero nitrogen-containing combustionproduced gaseous compounds from the oxidizing agent; and a pollutantremoval system including at least one direct contact heat exchanger forbringing the flue gas stream into intimated contact with a cooling waterto produce a pollutant-laden liquid stream and a stripped flue gasstream and at least one compressor for receiving and compressing thestripped flue gas stream and reducing the temperature of the strippedflue gas stream below the dew point of at least one of the condensablevapors in said stripped flue gas stream to separate the condensable andnon-condensable vapors.
 12. The integrated combustion system inaccordance with claim 11 including at least two heat exchangers and atleast two compressors.
 13. The integrated combustion system inaccordance with claim 11 wherein the stripped flue gas stream isseparated into non-condensable gases and condensable gases.
 14. Theintegrated combustion system in accordance with claim 13 wherein thecondensable gases are condensed into a substantially liquid state. 15.The integrated combustion system in accordance with claim 14 wherein thegases condensed into the substantially liquid state are sequestered. 16.The integrated combustion system in accordance with claim 15 wherein thegases condensed into the substantially liquid state are, in large part,CO₂.
 17. The integrated combustion system in accordance with claim 1wherein the carbon based fuel is a solid fuel and wherein the strippedflue gas stream is recirculated, in part, to carry the carbon based fuelinto the combustion system.
 18. The integrated combustion system inaccordance with claim 17 wherein the carbon based fuel is coal and/or amixture of coal and another solid fuel.
 19. The integrated combustionsystem in accordance with claim 18 wherein the stripped flue gas streamis substantially CO₂.
 20. The integrated combustion system in accordancewith claim 11 including a plurality of heat exchangers and compressors,wherein at least two of the heat exchangers are direct contact heatexchangers for intimately contacting cooling water with the flue gasstream and wherein at least one compressor is disposed between the heatexchangers for compressing the stripped flue gas stream between the heatexchangers.
 21. A combustion and integrated pollutant removal methodcomprising the steps of: operating a combustion system having at leastone burner that is configured to substantially, prevent the introductionof air; providing an oxygen supply for supplying oxygen at apredetermine purity greater than 21 percent; providing a carbon basedfuel supply for supplying a carbon based fuel limiting an excess ofeither the oxygen or the carbon based fuel to less than 5 percent overthe stoichiometric proportion; controlling the combustion of the carbonbased fuel to produce a flame temperature in excess of 3000 degrees F.and a flue gas stream containing CO₂ and other gases and substantiallyvoid of non-fuel borne nitrogen containing combustion produced gaseouscompounds; directing the flue gas stream to a pollutant removal systemwhich includes a direct contact heat exchanger in serial arrangementwith a compressor; enabling the flue gas to be placed in contact with acooling liquid in the heat exchanger to produce a pollutant-laden liquidstream and a stripped flue gas stream; discharging the pollutant-ladenstream; compressing the stripped flue gas stream to separate thecondensable and non-condensable vapors; storing the condensable vapors;filtering the non-condensable vapors; and releasing the balance of theflue gas to the atmosphere; feeding the stripper flue gas stream intothe compressor to compress the stripped flue gas Stream.
 22. The methodin accordance with claim 21 including the steps of cooling the strippedflue gas stream and compressing the cooled stripped flue gas stream. 23.The method in accordance with claim 22 including the step ofsequestering the compressed cooled stripped flue gas stream.
 24. Anoxygen-fossil fuel combustion system comprising: a combustion systemhaving a furnace having a controlled environment with substantially noin-leakage from an external environment, and configured to substantiallyprevent the introduction of air, an oxidizing agent supply for supplyingoxygen having a predetermined purity, a carbon based fuel supply forsupplying a carbon based fuel and including means for feeding the oxygenand the carbon based fuel into the furnace in a stoichiometricproportion to one another limited to an excess of either the oxygen orthe carbon based fuel to less than 5 percent over the stoichiometricproportion, recirculation of combustion products to aid in supplying acarbon based fuel and to improve heat transfer properties, and a controlsystem for controlling the combustion of the carbon based fuel toproduce a flue gas stream from the furnace having lownitrogen-containing combustion produced gaseous compounds from theoxidizing agent; and a pollutant removal system including at least oneheat exchanger for bringing the combustion product stream into thermalcontact with a cooling water to produce a pollutant-laden liquid streamand a flue gas stream stripped of a portion of the pollutants and liquidin the combustion products, and at least one heat exchanger andcompressor for receiving stripped flue gas stream and processing theflue gas stream to a temperature below the dew point of at least one ofthe condensable gases in the flue gas stream in order separate thecondensable and non-condensable vapors.
 25. The integrated combustionsystem in accordance with claim 24 comprising at least two heatexchangers and two compression stages.
 26. The integrated combustionsystem in accordance with claim 24 wherein the flue gas stream isseparated into two components using compression and cooling, onecomponent of which is substantially condensable vapors, and the other issubstantially non-condensable gases.
 27. The integrated combustionsystem in accordance with claim 26 wherein the condensable vapors arecondensed into a liquid.
 28. The integrated combustion system inaccordance with claim 26 wherein the condensable vapors are in asupercritical fluid state
 29. The integrated combustion system inaccordance with claim 26 wherein the condensable vapors include CO₂. 30.The integrated combustion system in accordance with claim 26 wherein theflue gas stream is cooled using condensate from the boiler feedwater tocool the stream to allow condensation.